Peer-reviewed veterinary case report
Tear test results vary by head shape in healthy dogs
By Bolzanni, Hellen et al.·Published in Veterinary ophthalmology·2020·School of Veterinary Medicine and Zootechny, Brazil·View original on PubMed →
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Original publication title: Aqueous tear assessment in dogs: Impact of cephalic conformation, inter-test correlations, and test-retest repeatability.
- Species:
- dog
Plain-English summary
A study found that brachycephalic dogs, like Bulldogs and Pugs, have lower tear production and corneal sensitivity compared to other breeds. This means that if your brachycephalic dog seems to have dry eyes or is squinting, it could be due to these issues. The researchers used various tests to measure tear production and sensitivity, and they discovered that stimulating the tear ducts can help increase tear production. If your dog is showing signs of eye discomfort, it’s a good idea to discuss these findings with your veterinarian for appropriate testing and treatment options.
People also search for: brachycephalic dog dry eyes · Bulldog eye problems · tear production tests for dogs
Abstract
OBJECTIVE: To characterize diagnostic findings, test-retest repeatability, and correlations among lacrimal tests in dogs of diverse cephalic conformations. ANIMAL STUDIED: Fifty healthy dogs (25 brachycephalic, 25 nonbrachycephalic). PROCEDURES: A series of diagnostics were performed in each dog, allowing for a 10-minute interval between tests and repeating each test 24 hours later under similar conditions: corneal tactile sensation (CTS), strip meniscometry test (SMT), phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT), Schirmer tear test-1 without (STT-1) or with nasolacrimal stimulation (NL-STT1), and Schirmer tear test-2 (STT-2). RESULTS: Mean ± SD test values were lower in brachycephalic vs. nonbrachycephalic dogs (except for SMT; 7.4 ± 2.0 mm/5 seconds vs 7.3 ± 2.4 mm/5 seconds), with statistically significant differences noted for CTS (1.8 ± 0.5 cm vs 3.4 ± 0.8 cm), PRTT (37.2 ± 4.0 mm/15 seconds vs 41.1 ± 5.5 mm/15 seconds), STT-1 (20.1 ± 3.4 mm/min vs 23.3 ± 5.7 mm/min), STT-2 (13.0 ± 3.4 mm/min vs 16.9 ± 3.9 mm/min), and NL-STT1 (23.2 ± 3.6 mm/min vs 27.1 ± 5.4 mm/min), and nonsignificant differences for EAPPTT (16.6 ± 2.7 mm/15 seconds vs 17.5 ± 2.9 mm/15 seconds). Nasolacrimal stimulation increased STT-1 values by 18% on average. Correlations among tests were generally weak to moderate (r < .70) except for a strong correlation between STT-1 and NL-STT1 (r = .83, P < .001). Test reliability was good although test-retest repeatability was generally poor to moderate, as depicted by low intraclass correlation coefficients (ICC ≤ 0.75) and wide 95% limits of agreement, except for CTS (ICC = 0.91). CONCLUSIONS: Corneal sensitivity and aqueous tear secretion are lower in brachycephalic dogs. A comprehensive assessment of the ocular surface requires the combination of several diagnostic tests. The nasolacrimal reflex may provide a useful diagnostic and therapeutic tool in dogs.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/32162773/